Sluggish starter but a full battery

[AREA]

Took the Chim for a good blast yesterday evening to make the most of a dry spell.

Got back home. Stopped the car for no more than 2 mins. Went back to start it and starter motor was really sluggish - slowly turning over just like with a flat battery. Check the voltage at the battery with a good enough 11.9v. Headlights were bright, fan came on, radio came on, but starter was just struggling.


Left the car to cool down for 30 mins, then it started fine.


Any ideas on what to check? This is not the standard hot start problem. I had the kit installed a year ago, along with a new starter motor for luck (and a relay bypass just in case the kit ever failed - nothing like extra redundancy in case of emergency!).

It would appear to be temperature related. Engine had been running pretty hard for about 45 mins and the radiator fans were on when I tried to restart the car; but with a sound battery unlikely to be current draw to the fans impacting the starter.

What should I check?

Thanks, Alex

[Hut49]

I'd start with the earthing points - I think there are 3 of them but I'm not near the Bible. BTW how old's the battery? Anymore than 3 years and I'd replace it while you're on that redundancy kick of yours

[AREA]

Great pointer! Thanks.... whilst looking for the earthing points, I came across the dreaded 100amp fuse. I'd heard of it but never had cause to go looking for it before. Took off the cover, all seemed ok, but thought "if I'm cleaning up earthing points, might as well clean every connection in the circuit". Took off one of the retaining nuts and the fuse fell into my hand (well nostril actually!). Had a complete straight split in it!

And it proved another thing to me... if you're lucky enough to be able to do it, wireless Internet access onto these forums when in the garage is an absolute Godsend!!

Thanks

[paulathome]

Area,
just a point, the 100 amp fuse is not in the starter motor circuit it's only between the alternator and the battery so would not effect starting.
Looks like you avoided a breakdown waiting to happen though.
Like the other guys I would say to check the earth points and also the connections at the starter motor for crud and rust. Take them off and clean with some emery paper. (with battery disconnected of course)
Cheers.
Paul.

[David Beer]

Many put an extra earth braid(heavy cable) from the battery neg to the engine block, to cure the slow crank, me included. You can enlarge the battery breather pipe hole, keep the length as short as possible.

[spend]

Is that because its too much trouble to ensure that the TVR main chassis earth and strap across the engine mount are serviced properly. Or is there some deficiency in the TVR design?

Dave

[Cider Andy]

Where did you measure the 11.9V? Across the battery terminals? After a long run and only having been stopped for a few minutes, I'd say that's not healthy: it should be reading above 12V.

If you did test the battery voltage at the terminals, check it again with the headlamps switched on. If the battery's healthy there shouldn't be a drop of more than about ½V.

[mdotrutherford]

Bumping up as I wondered if you had a fix on this Alex.

Changed by battery today due engine turning over slowely and sluggish lately - generally when cold, so ruling out H.S scenario I assume.
Blow me down not much better with the new one.

Is this a sympton of a starter motor that needs replacing due to the hot enviroment it lives in or does history show that units only
fail totally ie brushes/solenoid

Appreciate your thoughts please all

Hav'nt checked wiring/starter out as barely got a chance to replace the battery in between showers - let alone polish up for Brooklands
in the morning...... Oh the thought of it, starter failure in front of the TVR Massive tomorrow......

Brgds
Ian

[Ozstyle]

Hi,
agree on the failing battery theory. I found that when my battery was on the way out it struggled to start the engine and if the cooling fans were running it would not even turn over.

[AREA]

What I think happened is this:

1. 100 amp fuse cracked (I see a recent thread suggesting that this is not an uncommon problem). As a result:
2. Alternator was not charging up the battery
3. Voltage on battery had dropped to the point where cranking the engine over was just a tad too hard
4. As often happens with slightly discharged batteries, leaving a while allowed it to recover just enough to turn the engine over into life.

So, I went out and bought 50 of the damn fuses, have 10 in the tool kit in the car (so I can give them out as spares to passing Chim owners!), and bought a new battery to be on the safe side.

Two basic lessons here:
First, replace the 100amp fuse as part of the service regime; second, replace the battery every two years. Now what else can I find to replace on a regular basis that will bump up the ownership-cost-per-mile !!!!

[mdotrutherford]

Assume you are fixed up and all is ok now.

I am a happy bunny as I found my defect was the earth point front offside chassis. Cleaned it all up and it spins like a top on the starter now.
Glad I followed all the advice on the thread before buying a new starter as well as the battery. :-)

[spend]

You should have a light on the dash to warn you when not charging????

A bigger battery will last longer IMHO. Any battery will fail if it is not being charged.

Moving the fuse inboard will take it away from the damaging harsh environment, later cars did this I believe.

Dave

PS Starter earth is battery - chassis (under tunnel) & Chassis to engine mount (drivers side) ~ Front offside should only be for headlights etc in the front, you dont want to be putting starter current across those wires?

[mdotrutherford]

spend said:

PS Starter earth is battery - chassis (under tunnel) & Chassis to engine mount (drivers side) ~ Front offside should only be for headlights etc in the front, you dont want to be putting starter current across those wires?

That thought had occured to me too Dave, though as I got a such as good result
by cleaning the front one it has inspired me to check out the others.
IYO whats the tunnel location like for getting to?
Cheers
Ian